DNA repair protein XRCC4 is a ~38 kDa protein. DNA non-homologous end joining (NHEJ) core factor, required for double-strand break repair and V(D)J recombination. Acts as a scaffold protein that regulates recruitment of other proteins to DNA double-strand breaks (DSBs). Associates with NHEJ1/XLF to form alternating helical filaments that bridge DNA and act like a bandage, holding together the broken DNA until it is repaired. The XRCC4-NHEJ1/XLF subcomplex binds to the DNA fragments of a DSB in a highly diffusive manner and robustly bridges two independent DNA molecules, holding the broken DNA fragments in close proximity to one other. The mobility of the bridges ensures that the ends remain accessible for further processing by other repair factors. 1. Nick McElhinny, SA. et al. (2000) Molecular and cellular biology 20, 2996-3003. PMID: 107577842. Chen, L. et al. (2000) The Journal of biological chemistry 275, 26196-205. PMID: 108544214. Foster, RE. et al. (2006) Biochemical and biophysical research communications 341, 175-83. PMID: 164129785. Mari, PO. et al. (2006) Proceedings of the National Academy of Sciences of the United States of America 103, 18597-602. PMID: 171241667. Roy, S. et al. (2012) Nucleic acids research 40, 1684-94. PMID: 222288318. Wanotayan, R. et al. (2015) Biochemical and biophysical research communications 457, 526-31. PMID: 255979969. de Bruin, C. et al. (2015) The Journal of clinical endocrinology and metabolism 100, E789-98. PMID: 2574251910. Fukuchi, M. et al. (2015) Biochemical and biophysical research communications 461, 687-94. PMID: 25934149 | 
